JPS63155984A - White balance circuit for electronic endoscope - Google Patents

Abstract

PURPOSE:To display the object of image pickup in color with fidelity by obtaining the color temperature of a light source lamp and controlling the gain with respect to the signal of each wavelength in an image pickup signal of a solid-state image pickup element so as to apply white balance. CONSTITUTION:Sequential illuminating lights R, G, B reflected in a half mirror 66 are received by a photodetector 67, the, quantity of light is converted into an electric signal, inputted to an RGB synchronizing circuit 69 via an amplifier 68 to synchronize the R, G, B sequential signal electrically. Then the difference of the signals R, B with respect to the signal G is detected by differential amplifiers 91, 92 and its output signal forms R and B control signals controlling the gain at the input of R, G image pickup signal in the R, B sequential illumination picked up by a CCD 57. Then the R and B control signals are applied to a signal processing circuit processing the image pickup signal to obtain white balance. Thus, the white-balancing state is always maintained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention detects color temperature by receiving light from a light emitting source, and
The present invention relates to a white balance circuit for an electronic endoscope that adjusts the gain of each color signal q in a signal of &.

[Prior art] In recent years, by inserting an elongated insertion section into a body cavity,
An endoscope that allows you to observe the affected area within the body cavity using the observation means installed inside the insertion section, and perform treatment by inserting a surgical nail tool into the forceps channel as necessary, without requiring an incision. has become widely used.

In the above-mentioned endoscope, an image guide fiber is used for image transmission, but recently a solid-state imaging device such as a COD is housed in the distal end of the insertion section to form an imaging means, and this solid-state imaging device performs photoelectric conversion. An electronic family celebration system that transmits signals via cable and displays color images on a monitor device.
t (hereinafter referred to as electronic endoscope) has come into practical use.

By the way, the electronic endoscope described above requires white balance: A adjustment. In other words, when a white subject is imaged, the Machida time of the color separation rotary filter in the light source device is set in order so that the CCD output Shintan signal, G, B ratio is 1.
This R, G, [
No. 3, Showa DI The time was adjusted by changing the time electrically or mechanically, or the gain of each COD output signal was changed to adjust the timing. A more accurate expression of white balance is defined by the output signal from the device to a display monitor, etc., for example, by setting the ratio of R, G, B output signals to 1 or by setting N
In the TSC method, the number is (R-Y).

Set the color difference signal output of (B-Y) to O. In other words, the chrominance signal modulated by the subcarrier is set to 0'' when the uH image of the object is "white".

FIG. 11 shows a mechanical type of conventional white balance adjustment means.

As shown in the figure, the rotary filter 1 is rotationally driven by a motor 2, and by this rotation, fan-shaped red, green, and black color transmission filters are formed on the rotary filter 1, that is, R filter 3R, G filter 3G, 1B filter 3B. is interposed so as to cross the light beam 4 of the light source lamp (not shown), that is, in the middle of the optical path. Each color filter 3R, 3G, 3B
When each of these is inserted, the subject is illuminated with color-separated red, green, and blue light that passes through the light guide. Considering this, it depends on the irradiation light i1, that is, the irradiation time (exposure time). Therefore, white balance adjustment is performed by changing the frontage ratio of R, G, and B of the rotary filter 1, that is, the length of the fan-shaped fan. For example, R, G in COD output.

When the B ratio becomes 1, [R, G, B and NT as outputs]
Assuming that white balance can be achieved with the SC output, if a white subject is imaged and the COD output in that case is as shown in Figure 12 (a) 1, then the R filter 3R will have a fan The length is increased to increase the opening ratio, while for B filter 3B, the length of the fan is shortened to lower the opening ratio.
As shown in the same figure (11), R, G,
White balance adjustment is performed so that the ratio of B becomes 1.

On the other hand, there are some that adjust the white balance by electrically changing the exposure time.

There are two types of electrical adjustment methods: one that causes the light source lamp to emit light continuously, and one that causes the light source lamp to emit light intermittently using pulses.In the latter case, for example, as shown in Figure 13(a).
Light is emitted with an equal number of pulses (for example, 5 pulses) as shown in FIG.

As shown in the same figure (b), the COD output when a white subject is illuminated through the B filter is R, G.
, B deviates from 1, the white balance is deviated. In this case, as shown in FIG. 13(C), for example, using the G filter as a reference, increase the number of light emission pulses in the R filter, while decreasing the number of light emission pulses in the B filter for illumination. The exposure can be changed by
As a result, the COD output obtains R, G, and B signals with a good white balance, as shown in FIG. 2(d). still,
In this conventional example, the numerical aperture of each color filter is assumed to be constant.

FIG. 14 shows a conventional example in which white balance adjustment is performed by adjusting the gain of a COD output signal.

Electronic endoscope device 11 with white balance adjustment function
An electronic endoscope 12 incorporating an image carrier, a light source section 13 that supplies illumination light to the electronic endoscope 12, and an electronic endoscope 12.
! The signal processing section 14 converts the signal imaged in step 12 into a video signal that can be displayed on a display device.

The electronic endoscope 12 has an elongated insertion section 15 formed so as to be easily inserted into a body cavity, and an objective lens 16 and a CCD 17 as a solid-state imaging device are disposed on the distal end side of the insertion section 15 as an imaging means. is incorporated.

A lie 1-guide 18 for transmitting illumination light is inserted into the insertion section 15, transmitting the illumination light supplied from the light source section 13, and emitting it from the distal end surface. It is expanded by a light distribution lens 19 to illuminate the subject 11 side.

The light source unit 13 that supplies illumination light to the end surface on the proximal side of the light guide 18 includes a light source lamp 22 and a light source lamp 22.
a lens 23 that condenses and irradiates the illumination light onto the end surface of the light guide 18; and an RGB rotating rotary filter 24 that is interposed in the optical path between the lens 23 and the end surface of the light guide 18.
It consists of a motor 25 that rotationally drives this rotary filter 24.

The rotating filter 24 receives light in each wavelength range of red, green, and blue.
In other words, red, green, and blue transmission filters 24R, 24G, and 24B that transmit R, G, and B, respectively, are formed in a fan shape. It is designed so that the light is illuminated in sequence. The motor 25 that rotates this rotary filter 24 is
The rotation is controlled by a rotation servo circuit 27. As a result of this rotation servo circuit 27, the rotation of the motor 25 is synchronized with the frame frequency of the video signal.

Subject 21 illuminated sequentially with the above 8 lights of R, G, and G
is imaged by the objective lens 16 on the imaging plane of the solid-state Ha image element by the CCD 17, and the photoelectrically converted signal is read out by applying a readout clock signal by the COD driver 28. In this way, the 0x signal q and the signal of the rotation servo circuit 27 are synchronized with the synchronization signal output from the synchronization signal generator 29.

The output signal of the CCD 17 is amplified by a preamplifier 31 forming the signal processing section 14, and is inputted to a reset noise removal circuit 33 via an isolation circuit 32 that protects thoughts from electric shock, etc., where reset noise is removed. Thereafter, unnecessary high frequencies such as 1/f noise and CCD key 11 rear are removed through a low-pass filter 34, white balance adjustment is performed in a white balance adjustment circuit 35, and γ correction is roughly performed in a γ correction circuit 36. Non-linearity correction of the electrical/optical conversion system when displaying is performed and input to the A/D converter 37. still,
The electric signal-to-light conversion characteristic of a television picture tube is not linear, but usually γ = 2.2, and this γ correction circuit is used to correct this nonlinearity to a linear characteristic throughout the entire system via the electronic endoscope. The input/output characteristics of 36 are normally set to the reciprocal of γ=2.2, that is, γ=0.45.

The frame memory 38 is converted into a digital signal by the Δ/D converter 37 and supports frame-sequential illumination.
One frame each is written to R, 38G, and 38B. That is, for example, the image is carried under illumination with red light through the red transmission filter 24R, and the signal read from the CCD 17 is written into the frame memory 38R. When image data for one frame is written to each frame memory 38R, 38G, and 38B, these are read out simultaneously, each converted into an analog signal by a D/A converter 39, and roughly processed by a low-pass filter 41. Unnecessary high frequencies are removed at , and each of the signals is input to an output amplifier 42 . The conversion speed of the A/D converter 37 and the writing and reading of data into and from each frame memory 38R138G and 38B are controlled by an output signal from a memory control circuit 43. The output signal of this memory control circuit 43 is generated in synchronization with the synchronization signal of the synchronization signal generation circuit 29.

The R, G, and B color signals passed through each of the output amplifiers 42 are outputted from a primary color signal output terminal having an output impedance of 75Ω. Further, the composite synchronization signal of the synchronization signal generation circuit 29 is also outputted from the synchronization signal output terminal via the output amplifier 44.

By the way, the white balance adjustment circuit 35 is configured so that the output gain of the signal passed through the white balance adjustment circuit 35 can be variably adjusted by the white balance adjustment section 45. The white balance adjustment circuit 35 including this adjustment section 45 has a configuration as shown in FIG. 15, for example.

The non-inverting input terminal of the differential amplifier 47 forming a gain-controlled amplifier is connected to the input terminal of this white balance adjustment circuit 35, and the inverting input terminal is connected to its output terminal via a resistor RL. Variable resistor R1 and switch S
1. It is grounded via a resistor R2, a switch S2, a variable resistor R3, and a switch S3.

For example, as shown in FIG. 16(a), the input signal Vi is applied with signals VR, VG, and VB that are sequentially imaged under R, G, and B illumination, and the differential amplifier After being amplified through 47, the output signal VO is output from the output terminal.

The switches Sl, 82.83 are turned on and off by a control signal, for example, each switch 81.82. S
3, as shown in FIGS. 16(b), (c), and (d), during the period when the input signals VR, VG, and VB are input.
1-1" level. It is turned on by the R, G, and B control signals, and is kept off by other "L" levels. Therefore, for the signals VR, VG, and VB, the inverting input terminal is connected to a resistor, respectively. Since R1° is grounded through R2 and R3, the gains are (1+RL/R1), (1+RL/R2>, (1+
RL/R3).

Therefore, when the gain of the other two input signals VR and VB is variably adjusted using variable resistors R1 and R3 with respect to the level of the input signal VG, and when a white subject is imaged, the output of this white balance adjustment circuit 35 is input. ShingVR, VG, VG
This is to perform white balance so that the images are equal to each other.

[Problems to be Solved by the Invention] In the conventional white balance adjusting means described above, the setting itself is fixed, or only has manual adjustment by the user as an additional function.

Therefore, the color temperature changes from the time the power is turned on until the light source lamp or the color separation optical filter including the infrared cut filter becomes thermally stable, and is directly affected by changes in this area over time. The drawback was that balance could not be achieved.

The present invention has been made in view of the above points, and is an electronic endoscope that can maintain a white balance state at all times without depending on color temperature changes until thermal stability or changes over time. The purpose is to provide a white balance circuit for

[Means and effects for solving the problem] In the present invention, in the principle diagram shown in FIG.
The second light is passed through a lens 63 and an R, G, B color separation filter 64.
R, 64G, and 64B are attached, and a half mirror 66 is installed after the rotating filter 64 in the optical path that irradiates the incident end surface of the light guide 58 that is inserted into the electronic scope 52 via the rotating filter 64 rotated by a motor 65. R, G, B reflected by this half mirror 66
A photodetector 67 sequentially receives the illumination light, converts the R, G, and B lights a into electrical signals, and inputs them to an RGB synchronization circuit 69 via an amplifier 68. , G, and B sequential signals are electrically synchronized, and the difference between R and B is detected using differential amplifiers 91 and 92 with G as a reference.
The output signals of the differential amplifiers 91 and 92 form R control and B control signals that control the gain when the R and GI image signals are input when sequentially illuminating the R and B images captured by the CCD 57. The white balance is obtained by applying the O-ring signal to a signal processing circuit that processes the loading signal.

[Embodiment] Figures 2 to 7 relate to the first embodiment of the present invention, and the second embodiment
The figure is a block diagram showing the groove bottom of the electronic endoscope device in which the first embodiment is formed, FIG. 3 is a block diagram showing the configuration of the RGB synchronization circuit, and FIG. 5 is an explanatory diagram showing the relationship between the light intensity of each wavelength applied to the light source lamp and the color temperature, FIG. 6 is a configuration diagram showing the configuration of the gain control circuit 90, and FIG. FIG. 6 is a timing chart for explaining the operation of FIG. 6;

As shown in FIG. 2, an electronic endoscope system blue 51 equipped with the first embodiment includes an electronic endoscope (electronic scope) 52 in which an imaging means is incorporated, and supplies illumination light to this electronic scope 52. It consists of a light source section 53 and a signal processing section 54 that converts a signal imaged by the electronic scope 52 into an image signal that can be displayed on a display device.

The electronic scope 52 is designed to have a 1 liter capacity for easy insertion into the body cavity.
An insertion section 55 having a length of 1.5 liters is formed, and an objective lens 56 and a CCD 57 as a solid-state element are mounted on the distal end side of the insertion section 55.
An imaging means is incorporated by arranging and.

Further, a light guide 58 for transmitting illumination light is inserted into the insertion portion 55, transmits the illumination light supplied from the light source portion 53, and emits it from the distal end surface, and the emitted illumination light is distributed. It is expanded by a lens 59 to illuminate the subject 61 side.

The light source section 53 that supplies illumination light to the proximal end surface of the light guide 58 includes a light source lamp 62 and a light source lamp 62.
A lens 63 that condenses and irradiates the illumination light onto the end face of the light guide 58, a rotating filter 64 interposed in the optical path between the lens 63 and the end face of the light guide 58, and a rotary filter 64 that is rotationally driven. After passing through the rotating filter 64, a half mirror 66 disposed at a position a before the light is projected onto the end face of the light guide 58, and this half mirror 66 generates an anti-C) J-cN. It consists of a photodetector 67 that receives light and an amplifier 68 that amplifies the photoelectric conversion signal of this photodetector 67.

The light source lamp 62 emits white light from a xenon lamp shade, and has an emission spectrum distribution close to blackbody radiation.

The rotary filter 64 is composed of three fan-shaped color transmission filters 64R, 64G, and 64B.As shown in FIG. G.

It has the characteristic of transmitting B, respectively.

As shown in FIG. 2, the illumination light from the light source lamp 62 is condensed by a lens 63 and directed toward the incident end face of the light guide 58, but a rotary filter 64 rotated by a motor 65 is placed on the optical path. will be interposed. In other words, as the rotary filter 64 is rotated, a color transmission filter (blue transmission filter 64B in FIG. 2) is interposed between the lens 63 and the incident end surface of the light guide 58.
) The object 61 is sequentially illuminated (for example, R, G, B, R, . . . ) by light in the wavelength range. At the same time, a part (for example, about several percent) of the light incident on the incident end face of the light guide 58 is reflected by the half mirror 66, received by the photodetector 67, photoelectrically converted, and then converted by the amplifier 68. RG that is amplified to form a white balance circuit
The signal is input to six B synchronization circuits.

The rotational speed of the motor 65 that rotates the rotary filter 64 is determined by the rotation servo circuit 71 and the synchronization signal generation circuit 72.
control II to synchronize the phase with the frame frequency (for example, 29°97 MHz).

Subject 6 illuminated sequentially with the 8 lights of R, G, [3] above
1 is imaged by the objective lens 56 on the image plane of the CCD 57,
The photoelectrically converted signal is read by application of a read clock signal by the COD driver 73. Note that this clock signal q and the rotation servo circuit 71 are connected to a synchronization signal generation circuit 72.
synchronized to the synchronization signal of

The output signal of the CCD 57 is amplified by a preamplifier 75 forming the signal processing unit 54, and is inputted to a reset noise removal circuit 77 via an isolation circuit 76 for protecting the patient from electric shock, etc. /f
Noise, set noise, etc. are removed. Thereafter, unnecessary high frequencies such as COD carriers are removed through the low-pass filter 78 and input to the white balance adjustment circuit 81 . The white balance adjustment circuit 81 performs white balance adjustment, and the γ correction circuit 82 performs γ correction, that is, the nonlinearity of the electrical/optical conversion system when displaying on a display tube (usually γ-2, 2) is corrected (for example, γ = 1/2°2 = 0.42),
The signal is input to the A/D converter 83. This A/D converter 83 converts the signal into a digital signal, and the signal captured under frame-sequential illumination is stored in the frame memory 84R1.
848 and 84G are filled with one frame each.

That is, for example, an image is captured under illumination with red light through a light transmission filter 84R, and a signal read from the CCD 57 is written into the frame memory 84R. When image data for one frame is written to each frame memory 48R184G, 84B, these are read out at the same time, converted into analog signals by a D/A converter 85, and further processed by a low-pass filter 86 to remove unnecessary high frequencies. The R, G, and B signals from which the discontinuity of the signal generated during conversion to D/D has been smoothed are input to an output amplifier 87, respectively.

The conversion speed of the A/D converter 85 and the writing and reading of data to each frame memory 84R, 84G, 84B are controlled by an output signal from a memory control circuit 88.
be done. The output signal of this memory control circuit 88 is generated in synchronization with the synchronization signal of the synchronization signal generation circuit 72.

Color signals R and G amplified by the output 7 amplifier 87.

B is outputted from an output terminal having an output impedance of 75Ω. Also, the same Jllll of the synchronization signal generation circuit 72
The signal is also amplified via the output amplifier 89, and is amplified and output from the synchronization signal output terminal.

By the way, the six RGB synchronization circuits forming the white balance circuit of the first embodiment photoelectrically convert signals of R, G, and B color sequential illumination light by the photodetector 67, that is, R, G, and B.
Captures color sequential illumination signals and synchronizes them to produce R, G,
R, G from B output end.

Outputs day lighting signal. These R, G, daylight signals are
The R and B gain control signals are inputted to the gain control circuit 90 and are generated through two differential amplifiers 91 and 92 using the G illumination signal as a reference, and the R and B gain control signals are sent to the control terminal of the white balance adjustment circuit 81. is applied to perform gain control on the original COD@image signals of R, G, and B illumination that are sequentially input to this white balance adjustment circuit 81, and output them at a white balanced image carrier level.

The RGB simultaneous circuit 69 has a configuration as shown in FIG. 3, for example.

The R, G, and B color sequential illumination signals (amplified by an amplifier 68) from the photodetector 67 shown in FIG.
The signal is inputted to and integrated into the integral signal shown in the figure (b). This integral signal is supplied to the sample and hold circuit 102R, 1
02G and 102B and output from the sampling pulse generation circuit 103 as shown in FIG. 4(C).
, B sampling pulses PR, PG, PB, and are held as shown in FIG. After the three R, G, B color sequential illumination signals are input, the synchronized signals HR,
HG and HB are output.

The sampling pulse generation circuit 103 receives, for example, a signal synchronized with the rotation of the motor 65 inputted from the rotation servo circuit 71, and serves as the color transmission filters 64R and 64G in the rotation filter 64.

64B is on the optical path, and the sampling pulse PR is generated at the timing when it is rotated and withdrawn from a certain state.

It outputs PG and PB. Therefore, for example, the output of the photodetector 67 may be input to a comparator, and the one-shot multivibrator may be activated to output a sampling pulse at the timing when the output of the comparator changes from "HIf to L".

The sampling pulses PR, PG, and PB are input to the delay circuit 105 via the OR circuit 104, as shown in FIG. 4(d).
A reset signal RES shown in is generated, and this reset signal RES is applied to the reset terminal of the integrating circuit 101.
The integral output of the integrating circuit 101 is set to zero level. As this reset means, for example, an analog switch may be provided in parallel with the integrating capacitor, and this analog switch may be turned on by the reset signal QRES.

Signals HR and HG of the RGB simultaneous circuit 69.

t-+S is input to a gain control circuit 90 as shown in FIG. This gain control circuit 90 controls signals HR, H
Two differential amplifiers 91,92 each having a signal B applied to its inverting input and a signal HG applied to its non-inverting input.
and switches 81 and 82 interposed between the output end of each differential amplifier 91 and 92 and the output end of this circuit 90, and a switch that turns on and off the voltage output from the variable resistance end of the variable resistor VR. S3 and these switches 81.82.83
The RGB control circuit 106 controls the on/off state of the RGB control circuit 106.

The differential amplifiers 91 and 92 generate the synchronized signals HR,
In HG and HB, this signal H is based on the signal HG.
Difference (amplification) signal HG- between G and another signal HR
IR and HG-HB respectively, and the difference (amplified) signal HG-HR.

HG-HB becomes the R and G control signals input to the white balance adjustment circuit 81, and each switch 8
1. Applied via S2. The white balance adjustment circuit 81 is formed of, for example, an analog multi-layer filter 81', and is configured to adjust the R, G, and B input from the gain control circuit 90 to the CCDI image signal input via the LPF 78.
A signal that has been multiplied by the gain control signal and has a white balance is output to the next stage γ correction circuit 82 side.

The analog multiplier 81' is configured to be able to apply a bias voltage to the level input from the gain control circuit 90 side, and the multiplication factor is always positive 8.

Incidentally, the gains of the differential amplifiers 91 and 92 can be adjusted using gain setting resistors, etc., and the gains can be turned into gain control signals that can be used to achieve white balance. In addition, each differential amplifier 9
1.92 allows for offset adjustment.

Furthermore, the gain control circuit 9o is configured to be able to variably set the DC level in the G lighting signal @ period by adjusting the variable resistor VR, and the R, G, B gain control input from the gain control circuit 90 Depending on the signal, the signal passing through the white balance adjustment circuit 81 is made into a white balanced signal.

In addition, R, G to turn on and off switches 81.33.32
, Bi control signals CR, CG, RG [3
The ai' control circuit 106 generates these control signals from the signal from the rotating surf circuit 71 or from the output signal from the photodetector 67.

For example, when a white subject is intercropped, the CCD lid image signal becomes as shown in Figure 7(a) (R, G, and B are shown for simplicity, and the white balance is not maintained. case), R, G, B output from the photodetector 67
The illumination signal is also a signal similar to that shown in Figure 1 (a).
However, the timing is such that the illumination ends before the RlG and B illumination signals are input). Therefore, the RGB simultaneous circuit 69
R and B output from the gain control circuits 91 and 92 through
The gain control signals SR and SB are as shown in FIG. 7(b). These signals SR, SB and variable resistance VR
The signal @SG set in RG B fiII control circuit 1
The control signal @OR shown in FIG. 7(C) output from 06,
Switches 81.83°$2 are turned on by CG and CB, and when turned on, signals SR, SG, and SB are applied to the white balance adjustment circuit 81. Depending on the magnitude of the signals, the signals are input to the white balance adjustment circuit 81. The gain of the signal is varied. R as shown in Figure 7(a)
, G, B input signals, HR-HG is positive, HG
-HB becomes negative, and in each input signal period RG B i,
11120 circuit 106 switches 81, 83 . S2 are respectively turned on and these gain control signals SR.

When SG and SB are applied to the white balance adjustment circuit 81, and the multiplication factor is 9 when the level of SG is O, for example, the gains for the R, G, and B input signals are q + α, g
, a-β. Therefore, the output signal through the white balance adjustment circuit 81 is as shown in FIG. 7(d).
The output signal is automatically set to a white balanced output signal in which each output level is equal.

According to this embodiment, R, G,
Since the B illumination signal is taken in/v and its intensity is detected, even if the color temperature of the light source lamp 62 changes, white balance can be achieved without incurring shadow costs. That is, the color temperature is detected, and the gain when passing through the white balance adjustment circuit 81 is adjusted according to the color temperature. For example, in Figure 5, when the value is 5000, the R, G, and B illumination light intensities are equal, and in this case, the gains are equal.As the color temperature becomes lower, the light intensity becomes as shown by the dotted line, and the white color changes accordingly. The gain of the balance adjustment circuit 81 is reduced for B illumination light, and increased for R illumination light, resulting in a white balance. Furthermore, even if the color temperature becomes high, the gain is adjusted accordingly to maintain white balance.

FIG. 8 shows main parts in a second embodiment of the present invention.

In this second embodiment, in FIG. 1 or 2, the light reflected by the half mirror 66 is incident on one end of, for example, a single fiber or equivalent fiber 111 of the fiber bundle forming the light guide 58, The light emitted from the other end of the fiber 111 is configured to be received by a photodetector 67. The fiber 111 used has a length equal to the length of the light guide 58. Incidentally, the fiber 111 is formed into a loop shape for miniaturization.

The rest is the same as the first embodiment.

According to this second embodiment, since the white balance is performed using illumination light that is almost equal to the illumination light directly emitted from the output end of the light guide 58, the light guide 58 exhibits wavelength dependence, for example. In this case, for example, even if the illumination light emitted from the output end face of the light guide 58 deviates somewhat from the white balance state, the deviation can be corrected to produce a white-balanced imaging signal. (In the first embodiment, when the transmission characteristics of the light guide 58 exhibit wavelength dependence, the R, G and
Even if the light intensity level of the B-color sequential illumination light is the same, the light level of the output fJJfa of the light guide 58 is different, and even if the B-color sequential illumination light deviates from the white illumination, the deviation is automatically corrected. However, in the second embodiment, since it is performed at the output end level, it can be made independent of the transmission characteristics of the light guide 58. ) FIG. 9 shows a third embodiment of the present invention. In this third embodiment, the output of the amplifier 68, that is, the signal in FIG. 4(a) is Δ/
The signal is input to the memory 122 via the D converter 121.

Therefore, the CPL 1123 plots the light emission intensity Do, DG, DR against the wavelength (red, green, blue) as shown in FIG. 10 from the data written in the memory 122, and this plotted point determines the color. Detect temperature T.

Therefore, the deviation of the color temperature from the desired color temperature, for example 5000K, is determined, and the ROM determines how much the gain should be increased or decreased for red and blue input signals, for example, with green as the reference.
124 data. Therefore, the variable gain amplifier 1 forming the white balance adjustment circuit 81
A gain control signal is output to the variable gain end of the variable gain amplifier 125, and the output signal that has passed through the variable gain amplifier 125 is automatically adjusted to a white balanced signal. In each of the above embodiments, the illumination light is not limited to R, G, [3 sequential illumination;
It can also be applied to +G+B, B and other sequential illuminations. Also, 3
The illumination is not limited to color sequential illumination, and may be four or more colors. Furthermore, even under white illumination, it is possible to separate the image into R, G, and B and perform white balance using the same method.

[Effects of the Invention] As described above, according to the present invention, the color temperature of the light source lamp is determined by receiving the light from the light source lamp, and the gain for each wavelength signal in the carrier signal of the solid silver image element is controlled. Since the white balance is set using the white balance, it is possible to compensate for white balance shifts over time caused by the color temperature of the light source lamp, the transmission characteristics of the color separation filter, etc. Can be displayed in color.

[Brief explanation of the drawing]

FIGS. 1 to 7 relate to the first embodiment of the present invention.
The figure is a principle diagram without showing the concept of the first embodiment, FIG. 2 is a block diagram showing the configuration of an electronic endoscope device in which the first embodiment is formed, and FIG. 3 is a diagram showing the configuration of an RGB synchronization circuit. Block diagram,
Figure 4 is a timing chart for explaining the operation of Figure 3;
FIG. 5 is an explanatory diagram showing the relationship between the light intensity of each wavelength and color temperature in the light source lamp, FIG. 6 is a block diagram showing the configuration of the gain control circuit 90, and FIG. 7 is a diagram for explaining the operation of FIG. 6. Timing chart diagram, FIG. 8 is a configuration diagram showing the main part of the second embodiment of the present invention, FIG. 9 is a 1-configuration diagram showing the main part of the third embodiment of the invention, and FIG. Characteristic diagram for explaining the operation of the figure,
Fig. 11 is a clear diagram showing a conventional white balance rotating filter, Fig. 12 is a waveform diagram for explaining the operation of Fig. 11, and Fig. 13 is an illustration for explaining the operation of the conventional example of the pulse emission method. A waveform diagram, FIG. 14 is a configuration diagram showing an electronic endoscope device having a conventional example, FIG. 15 is a circuit diagram without showing the white balance adjustment circuit used in FIG. 14, and FIG.
5 is a waveform diagram for explaining the operation of FIG. 5. FIG. 51... Electronic endoscope device 52... Electronic endoscope 53
...Light source section 54...Signal processing circuit 57.
・・CCD 62 ・・Light source lamp 64 ・・
・Rotating filter 66...Half mirror 67...
Photodetector 68...Amplifier 69...RGB simultaneous circuit 81...White balance adjustment circuit 90...Gain control circuit 91.92...Differential amplifier Fig. 1 Fig. 3 ,,,69 Fig. 4 Fig. 5 Fig. 6 Fig. 8 Fig. 9 Fig. 10 Proceedings (written by the author himself) July 1, 1985 Director General of the Patent Office Kunio Ogawa 1. Indication of the case Patent application filed in 1988 No. 303288
No. 26 Title of the invention White balance circuit 3 for white balance endoscopes, relationship with tenant ownership of the person making the correction Patent applicant address 2-43-2, Hasgaya, Shibuya-ku, Tokyo Name (037) Olympus Optical Industry Co., Ltd. Representative Satoshi Shimoyama Department 4, Agent 5, Amendment Order Day E 1 (Voluntary) 1, Mei IAM
On the 18th and 19th lines of the second page of +, there is a line that says "...irradiation time...".
Irradiation time... Correct the irradiation time to...''. 2. In the 1st and 2nd lines of the 4th page of the specification, [・
...Irradiation light...Irradiation time...]
Irradiation light...irradiation time..." will be corrected. 3. On the 16th line of page 6 of the statement, the text [...concentrated irradiation...] will be corrected to [...concentrated irradiation...]. 4. In the second and third lines of page 8 of the specification, “・
. . Reset noise . . . COD . . ." After that, it passes through the low-pass filter 34 and then the COD...
” will be corrected. 5. On the 16th line of page 12 of the specification, the text "...irradiation..." should be corrected to "...irradiation...". 6. In the 6th line of page 13 of the specification, “...R1G
The text "11ll statue..." has been corrected to "...R, Bhii statue...". 7. In the first line of page 15 in the details, the text [...concentrated irradiation...] will be corrected to [...concentrated irradiation...]. 8. On page 15 of the specification, lines 6 and 7, [
It says [Irradiated by...]
..." will be corrected. 9. In the 20th line of page 15 of the statement, the text "...irradiation..." should be corrected to "...irradiation..." 10. In the 9th line of page 16 of the specification, the text "...irradiation..." will be corrected to "...irradiation..." 11. In the 18th line of the 17th page of the Book of Meill, it says, ``...
・-0,42...” is replaced with “・・・-〇,45・
..." will be corrected.

Claims (1)

[Claims] An electronic endoscope device using a solid-state image sensor as an imaging means, comprising: a photoelectric conversion means for detecting the intensity of light from a light emitting source through an optical filter; The color temperature of the light emitting source is detected by calculating two or more of the signals containing three wavelength ranges such as green and blue, and the level of red, green, blue, etc. of the output signal of the solid-state image sensor is detected. A white balance circuit for an electronic endoscope, comprising gain control means for automatically setting a predetermined setting value.